Alternating-current converter



ALTERNTNG CURRENT COI.,

Filed March 7, 192.

WW W

MMM/MEM:

.June L 1929., N. M. @mw/wm XLTERNAT I NG CURRENT CONVERTER K Filed March 7, 1922 4 Sheetsheet 2 lun" June 11, 1929. Nl Ml HOPKINS 1,716,777

I ALTERNATING'CURRENT CONVERTER Filed March 1922 4 Smets-Sheet 3 June 1 1, 1929. N. M, HOPKWS 1,716,777

ALTERNATING CURRENT GONVERTR Filed Maren 7. 1922 4 sheets-sheet 4 Parana-@UF llEiL MONROE HOPKNS, OF NEW YORK, N. Y., `ASSIGrNOIR, BY MESNE ASSIGNMENTS,

TO NATIONAL CAR-BON COMPANY, INC.,

NEW YORK.

OF NEW YORK, N. Y., A CORPORATION OF v ALTERNATING-CUFRENT CONVERTER,

Application filed March?, 1922. Serial No. 541,813.`

This invention lrelates to alternating current converters of a type embodying a recti` I'ier and current and potential altering means adapted to render alternating current of fromv 110 to 220 volts suitable for supplying direct current to electrical apparatus, as in charging storage batteries.

. Vibratory rectifiers heretofore employed in suoli apparatus' have given more or less lo trouble because of `destructive arcing at the rectifier contacts,- caused generally by spawled off particles of the contacts lodging 'therebetween and short-circuiting them. Such converters havefalso generally been designed for use on but a single voltage, and the heat developed during operation has not been satisfactorily dissipated to avoid overheating the contacts'and injuring the windings. Y

c The principal object-s of the invention are therefore tov provide improved potential 'altering and rectifying means in` which short-circuits between the rectifier contacts shall be promptly interrupted to avoid sustained arcing and destruction of the rectifier contacts; to provide means for more readilyA dissipating the heat developed at the con-- tacts of the rectifier and in theseveral Windings and cores of the apparatus; and to provide a current converter which may be coupled to supply circuits having a Wide rango of voltages and one thatvis especially adapted for use in charging storage .batteries, arranged so that one or more storage batteries 'may be charged, as desired, Without complicated adjustments of the rectifier or other parts of the apparatus.

Generally speaking, the above and other objects and advantages are attained by providing a `quiclracting automatic switch to interrupt. the supply circuit to the rectifier K when ajshort circuit occurs at the rectifier contacts and to restore the current supply when the causeof the short circuit isl removed; by providing improved rectifier contacts and supporting means therefor; by providing, ample cooling mea-ns for such contacts and the vibrating means associated therewith; and by providing a variable impedance lhaving taps Where-by the voltage of the charging circuit may be changed to charge one or several storage batteries-'as desired. y

' The abovev and other'bjects and the novel ployed.

latter. south Apoles of the magnet P alternately atfeat-ures of the invention Will be apparent from the following description taken with the drawing, in which, Figure Vl is a side elevation of one type of improved electric current converter embodying the present invention; Figure 2 is a top plan view of the same; Figure 3 isa vertical 'sectional` view of the same, taken on the line of 3-3 of Figure 2; Figures 4l, 5 and are 'detail views of the construction of the stationary contact and its supporting means; and Figure '7 `is a 65 diagram of the Wiring of the apparatus.

As illustrated, one advantageous 'embodiment of the 'invention comprises a variable impedance I that has a winding T, one terminal of which may be connected to an alternating current supply main and which may be provided with a number of taps a, Z), c and d, any one of which may be connected to the delivery circuit of the con- Y verter` depending upon the amperage and voltage desired orvthe number of storage batteries to be charged therefrom. Therectifying device, which may be of any suitable type, is associated with the impedance coil I and herein comprises a vibratorl rectiier R, the vibrator V .of which vibrates in synchronism with the alternating current supply circuit and carries the contact K that cooperates With the contact C to open and close the supply circuit to rectify one half of each Wave of the alternating current. Other types of rectifiers may be cm* The actuating means for the vibrator V comprises a Winding -lV in series with the alternating current supply circuit and arranged to alternately induce poles of opposite polarity at the ends of the iron or steel vibrator which has a free movable end extending between the poles of a vpermanent magnet P.

T he rectifier also has a Winding lV that is connected in seriesv with a resistance R and through a switch across the alternating current supply mains X, Y so as to alternat-ely induce lnorth and south poles in the vibrator V and initiate the vibration of the The opposed permanent north and tract and repel the free end of the vibrator V as vits polarity alternates and thus close the deliverycircuit at the contacts C, K during each alternate half Wave of the alternating current. After the Winding W has started the operation ot the vibrator, the winding W cooperates therewith to continue such vibration.

Buring the operation' of the rectifier, there are times when injurious .arcing occurs at the'contacts C and K, as when par ticles spawl ofi' and lodge between the contacts, thereby maintaining a circuit between the contacts. Under such conditions vthe fuses in the supply circuit to the rectiier will ordinarily blow and interrupt the functioning ofthe rectifier until the fuses are replaced. Furthermore, such arcing inf ,juriou'sly aHects the contacts and in most cases if the arcing' continues too long the contacts must also be replaced, all of which detracts :trom the utility ofthe rectifier, adds to the expense involved in renewing such contacts and the time lost in its use. Accordingly, an automatically acting switch S is provided which is designed to quickly openthe supply circuit of the rectifier to interrupt the arcing and to permit the contacts C and K to sepa-rate and the particles therebetween to become dislodged.

The switch S is also designed to promptly reclose the supply circuit so that the rectifier will be again set in operation after the cause of the short circuit is removed. The switch S is operated automatically by the change in the value of the magnetic flux setup in the variable impedance by the`short circuit,

and when the latter is removed, the flux conditions in the impedance becomes normal and the automatic switch recloses the circuit to Apermit the continuation ofl the rectifying operation.

A The variable impedance may be of any desired construction and as herein `illustrat` ed comprises a central hollow laminated viron core l0, formed of athin strip of suitthat the turns of the core strip will not be magnetically short circuite'd by the ends of the yoke plates.4 The yoke plates 11. may be entirely of magnetizable metal or both magnetizable andV non-magnetizable metal,

' and provide metal paths for the magnetic 1 iux induced by the winding T and also serve as heat-radiating fins for dissipating the heat developed in the impedance. Thet yoke plates 11 may be clamped into position on the core' leg 1,0 by the end rings 13, and extend radially. from the' outer side of the central .core leg 10, having intermediateportions 14 which are spaced from the outer maar?? surface of the core leg 10 to provide a space to receive the winding T, which is desirably so arranged that its internal diameter is yokes 11, said spool having notches 181 in its flanges to receive the yokes edgewise and an internal diameter that4 is larger than the outside diametervof the core leg '10 to leave the air space 15. The end rings 13 may .be secured to the flanges of the spool 18 and the taps a, Z), c and d of the winding T may be connected to the binding posts as illustrated so that they will be accessible for the connection thereto of wires leading to storage batteries to be recharged.

The rectiier proper may be mounted beside the impedance or, as illustrated, upon the impedance I, posts 20 being provided onthe upper ring 13, upon which the base plate 21 may be secured to provide a space between therectitler head and the impedance to receive a part of the automatic switch which depends for its operation on changes of the value of the :flux in the variable' impedance. The base plate 21 supports the windings WV and W which are desirably wound'on a spool 24 secured to the base plate 2 1' and having a central passage that is coaxial with the two passages through and around the central ,core leg .10. The vibrator V is disposed within the V may be ofV steel or other magnetizable .I metal and its upper free end extends bef tween the north and south poles of a permanent magnet `P that is supported onv the upper side of the spool 24. The vibrator fcarries the contact K which is desirably a disc of Icopper or other suitable metal se-` cured by a tapered pin 281 to the upper free end of a leaf spring 28 having its free end secured 'to an oiset portion 281 near the lower end of thevibrator V, thereby separating the free ends of the spring and vibrator. To render the vibrator spring responsive to various alternating current frequencies a clip 29 may be provided, that is adjustable along the vibrator and spring to change the period of the latter. NQrmally the vibratoris disposed so that the contact K is separated from the stationary contact Ciwith which it cooperates and the spring 28 to provide a quick break when the vibra-` tor operates to open the contacts.

The stationaryl contact C, as shown, is comparatively massive and desirably consiste of a cylindrical block of carbon that is `press fitted in a cylindrical cup member 30 carried at the end of an adjusting screw 31,v The screw 31 is adjustably fitted in a mount-` detent 351 to retain the screw 31 and the contact C in their adjusted positions but enabling the screw to be readily turned in either direction at will. A removing pin 32 extends through the adjusting screw l31 and has a head 321 at its linner end that seats in the bottom ofthe cup 30'and in acorre- 'spending recess in the contact C. The pin 32 is threaded at its outer end to receive athumb-nut 322 whereby the pin 32, wheel 3 4 and screw, 31 lare vdetachably secured tof gether on. the 'mounting 33. Upon removal of the nut 322, the pin 32 may be driven out so as to force thecarbon contact C out of the cup 30 to permit replacing it. The head 321 on the rod'32 has a press fit in the corresponding recess in the contact C-so `that thelatter-is held tight regardless of the eX- pansion of the cup 30 and prevented from vibrating within its holder at allv Working temperatures.V The mounting 33 is remov-..

ably fitted in a recess 331 of the massive heat dissipating block or member 36, the members 33 and 36 having interfitting tongue and groove means 333l and 363 to connect the members, and the member 36 having threaded pins 354 secured thereto vadapted to passvthrough holes 334 in the member 33l andv arranged to receive thumb-nuts 335 whereby the mounting member with the carbon contact and its adjusting means are arranged so that they may be readily removed as a unit from the vsupporting block 36.

The block 36 may be mounted on the permanent magnet P, as shown, and may have heat radiating fins 365. The spring detent 351 maybe secured in a recess 352 in ther mounting Both the permanent-magnet P andthe block 36 have passages there-A through to permit the free circulation of air, thereby coolingv the impedance I, the windings 1V and W', andthe contacts C and .may be arranged soas to engage the contact supporting spring 28 to conduct heat therefrom. As illustrated, the heat dissipating member D comprises a strip of rethe )er si massive nea ssipating member bent upwardly andl v'then down. that its free end engages the rear side of the spring 23 adjacent to the contact K, when the vibrator V .is at one end of its movement. The spring D thus provides a resilient abutment for the vibrator, as well as a means for keeping the copper contact below a rapid vaporization temperature.

During the operation of the rectifier small particles of carbon'contact C spawl ofi' and sometimes lodge in the spacey between the contacts C and K, short circuiting the alternating current supply circuit and causing injurious arcing at the said contacts. To overcome the objectionable features of such short circuiting and arcing, a quick automatically acting means has been provided for interrupting the supply of current to the recitifier during such injurious arcing and for automatically re- Vclosing the supply circuit when such arcing hasv ceased. The operation of the vautomaticircuit or excessive areing at the contacts C andV K. The excessive ow. ofr current through impedance winding T..greatly"ir'1,v creases the magnetic flux or .the inductance in the core of the impedance which is accordingly employed as the actuating means for operating an electric switch controlling the supply of current to the rectifier. The mag,-A netic switch may4 take various forms, vand -as herein illustrated in Figures vl, 2 and 3 consists of anv electro-magnetic'.switch S which has a double-arm lever pivotedat 43, one arm 44 of which projects into the space between the upper end o f the core leg 10 and the base plate 21 whereit is disposed in the electro-magnetic field of the core of the impedance I. The arm 44 may be provided withan opening 441 inline with the central opening through the core leg 10 so that this arm will not interfere `with ther circulation of air through the apparatus. vThe other arm 45 of the switch lever vextends upwardly' and carries a pair of electrical switch vcontacts 451 near its upper endI whichcooperate with a pair of carbon switch contact-s 452 and 453 mounted on and insulatedv from a bracket 48 supported on the upper end ring 13. Suitable binding posts areprovided for connecting the alternating current line to one of the switch contacts '452 and for connecting the other switch contact 453 to the winding T. The switch is accordingly a single pole double break switch which opens one -side of the line when the magnetism `of the impedance core is suiiiciently strong to attract the arm .44. A short circuit at the rectilier contacts causes a magnetic supersaturation of the llO core l producing sufcientmagnetism to puli the switch arm 44 downwardly to open the switch contacts in series with the supply main leading tothe winding T. During this interruption of the circuit the winding 'W5 of the rectifier con:

ytinues to polarize the vibrator V, the lattervibrating and thereby dislodging any particlecaught between the contacts. After the' short circuit is removed, the magneticy condition Aot the core restores to normal, the

- rectifier resumes operation.

switch recloses the supply circuit and the spring 50, having one end secured to a bracket 48 l and the other end 'secured to the arm 45, holds the switch in a closed position,

and will restore the switchto closed posi-l tion after the interruption cfa short circuit.

' A single line 'switch M having blades m and m is arranged to sucessively close the main line circuit to the shunt coil l/V and to tl -ioad line L'Y.A Accordingly, the apparatus is'self-starting, and always starts ofi with the same polarity, and whenI the switch M is opened the battery will 'be prevented from discharging backthrough the apparatus. A suitable ammeter may be connected in the charging circuit and the apparatus may be enclosed in asuitable protective portable casing.

The operation of the improved converter will be apparent from the foregoing description. While the apparatus illustrated only. rectifies alternate half'waves of the alternating currentI it will be understood that the principles disclosed may also be employed in apparatus which rectifies successive-` half waves. The improved apparatus may be employed on alternating current mains of 110 or 220 volts ot various frequencies to economically charge from one tosix six-volt storage batteries or three twelve-volt batteries in series at a five ampere rate. The

` rectifier contacts are the only elements which deteriorate to .any extent and may readily 'be'renewed at small expense. It

will be understoodv that the construction of the limproved converter may be modified without departing from the principles of the invention, which is accordingly not limited tothe details disclosed.

l claim l l. Thecombination with an electrical rectifier comprising cooperating contacts and,

means for startingthe operation of one of said contacts before the closure ot' the circuit including said contacts, and means wherebythe circuit including said contacts is automatically opened when a short circuit occurs and whereby said circuit is reclosed upon removal of such short circuit, such starting means being adapted tocontinue the operation of said one contact4 during the interruption of the circuit throughv said contacts. i

Normally a 2. The combination with an electrical rectiiier having cooperating contacts, a magnetizablecore, a winding on said core in circuit with said contacts, andan electromagnetic switch controlling the` circuit or" said contacts and winding and having an operating member adapted to be attracted by said vcore to open said switch when a short cirving and in circuit therewith, a potential altering device having a winding coaxial with saidmagnetizing winding and in circuit with the latterbut spaced therefrom, and means extending into the space'sbet'ween said windings and operable to interrupt the low ofcurrent therethrough.

5. Electrical apparatus comprising a substantially annular support, a movable' con tact within saidsupport; a stationary contact cooperating therewith, amounting for the latter, means on said mounting wher'eby said stationary contact may beI adjusted relas A,.

Vtively to said movable contact, and means 10o whereby said mounting is removably secured to said sup ort. y i i- 6. Electrical apparatus comprising a contact, an adjustable holder therefor having a recess receiving said contact, and removable means in said recess to which saidcontact is secured and operable to force said contactfrom said holder.

7. Electrical apparatus comprising a contact, Aan adjustable holder therefor having a recess receiving said contact and a passage communicating with said recess, and a ref movable rod projecting through said passage llO into said recess and secured to said ycontact substantially normal to the contacting face of the latter whereby said contact may be forced from said holder by the removal. of

.8. Electrical apparatus comprising a contact of carbon', an adjustable holder therefor having a recess in which said contact tits tightly, and a removable member in said recess 'onto which said Contact is tightly fitted and whereby said contact may be forced from said holder. l l' 9. Electrical apparatus comprising a contact,A a mounting, an adjustable holder on l said mounting having a recess receiving said contact, said holder having a passage .thereremovable rod projecting-through said pas-l through communicating with said recess, a l

' vibrator disposed `in sage and secured to the rear side of said contact, a handle vfor adjusting said holder, and means for securing together said rod, handle and holden 10. An electrical rectifier comprising an o eratin 'Windln a "starting winding, a the coincident axes of said windings and in circuit with said operating Winding, an adjustable stationary contact, and a contact carried by said vibrator cooperating with said stationary contact.

11. An electrical rectifier comprising a,

' spool, an operating winding on said spool, a

vibrator disposed substantially inthe axis of said spool, a polarizing magnet mounted on said spool and arranged to cooperate with said vibrator, a massive heat-dissipating member mounted on said polarizing magnet7 an adjustable stationary Contact mounted on said heat-dissipating member, a contact yieldably mounted on said vibrator'and cooperating With said stationary Contact, and a resilient heat-dissipating abutment for the vibrator Contact.

Intestimony whereof, I affix m signature.

NEVIL MONROE H PKINS. 

